1. Field of the Invention
The present invention relates to an electromagnetically actuated injection valve.
2. Description of Related Art
One type of known injection valve has a fixed core and a movable core which faces the fixed core. With such an injection valve, a seat member on the movable core has increased area to interact with the fixed core thus achieving the same attraction power with fewer coil winding turns and a smaller diameter injection valve.
An example of such an injection valve is seen in JP-U-61-66659 wherein a magnetic circuit is formed by a yoke, a stopper, a fixed core and a movable core which are made of magnetically permeable material. The stroke of the movable core is limited by the stopper.
However, according to the injection valve disclosed in JP-U-61-66659, when remanent magnetization remains in the stopper, the opening and closing valve responses to opening and closing control signals are deteriorated.
Furthermore, since the stopper area intereacting with the movable core is large, in addition to increased remanent magnetization, so called "squeeze phenomenon" or "linking phenomenon", which connect two proximately located materials happen when the coil is energized. This "squeeze phenomenon" or "linking phenomenon" also acts to deteriorate the closing valve response.
Furthermore, such a seat member requires a flat spring to prevent fluctuation and/or deflection of the movable core when the movable core moves.